1. Field of the Invention
The present invention relates generally to formulations for and a method of making color-stable syrup concentrates and beverages. More particularly, the invention relates to preventing decoloring or fading of syrups and beverages containing vitamin C (L-ascorbic acid) and an azo food dye using riboflavin (vitamin B2) as a color stabilizer.
2. Description of Related Art
Depending on the ingredients employed, beverage formulators in the past have experienced color stability problems, such as decoloring or discoloring of beverage compositions. As used herein, "decoloring" means causing the fading or loss of color imparted by a dye to a solution, for example, bleaching of the dye. This term, "decoloring," is to be distinguished from "discoloring" as used herein, which means imparting an undesired color to a formulation.
Various approaches have been tried in the past to solve different problems relating to the color stability of beverage formulations, especially beverage compositions fortified with vitamins and/or minerals.
U.S. Pat. No. 4,992,282 to Mehansho et al. is directed to problems caused by the presence of both vitamins and minerals, such as iron, in beverages. Iron supplements tend to discolor foodstuffs, i.e., iron sources tend to impart an undesirable color to beverage compositions (see also U.S. Pat. No. 5,002,779 to Mehansho et al.). The Mehansho et al. ('282) beverages are fortified with vitamin C, riboflavin, vitamin A, iron and calcium compounds, and may include other vitamins, such as vitamin B6, niacin and vitamin B12. The vitamin and mineral ingredients can be formulated in concentrated syrups which may contain, in addition to water, sugars, flavors and colors. The syrup compositions are diluted with water to make the final low-pH beverages.
Mehansho et al. ('282) discuss the problem of discoloration of beverages fortified with iron, rather than the problem of decoloring of beverage compositions fortified with vitamin C. However, others have attempted to solve the color instability problem, i.e., the fading of the dyes in beverages, resulting from the chemical incompatibility of certain food dyes in the presence of vitamin C.
For example, U.S. Pat. No. 4,208,434 to Iacobucci et al. is directed to forming color-stable food compositions which contain an anthocyanin pigment and vitamin C. Anthocyanin pigments are incompatible with ascorbic acid. Iacobucci et al. attempt to solve this problem by using certain ascorbic acid derivatives which do not bleach anthocyanin pigments as rapidly as ascorbic acid. Thus, Iacobucci et al. deal with a color-stability problem caused by the use of anthocyanin pigments in combination with ascorbic acid, rather than the use of azo dyes in combination with vitamin C.
Solutions containing vitamin C and azo dyes have been known to discolor over time. Difficulty has been encountered in maintaining the color over long periods of time of beverages fortified with ascorbic acid, such as sport-type drinks formulated to help optimize the performance of athletes. Ethylenediaminetetraacetic acid (EDTA) helps stabilize the color of beverages containing an azo dye and vitamin C. However, under current U.S. regulations, EDTA cannot be used in still beverages. Thus, other ways to stabilize the color of beverages fortified with vitamin C are needed.
U.S. Pat. No. 3,958,017 to Morse et al. is directed to the use of cysteine to form color-stable beverages containing vitamin C, a food dye such as an azo dye, and optionally, iron. U.S. Pat. No. 3,652,290 to Hammes et al. discloses the use of histidine, glycine or methionine similarly to protect vitamin C in beverages containing a food dye such as an azo dye, and thus improve color stability.
Although Morse et al. and Hammes et al. suggest an approach to forming color-stable compositions containing both an azo dye and vitamin C, it would be desirable to produce syrup and beverage formulations containing an azo dye and vitamin C with even better color stability. Moreover, it would be desirable to form colorfast syrup and beverage formulations containing an azo dye and vitamin C without the necessity of using cysteine, histidine, glycine or methionine amino acids. It would also be desirable to find a color stabilizer which provides for colorfast azo-dyed beverage formulations fortified with vitamin C which even contain an additive such as a glassy sodium polyphosphate (e.g. a compound of the formula (HPO.sub.3).sub.n.Na.sub.2 O where n=13 to 21) which, in the absence of the color stabilizer, undesirably accelerates the fading or decoloring of the formulation.